Eligible subjects will be randomly allocated to receive three doses Namisol® (3 mg or 5 mg or 6,5 mg) and placebo in double-blind crossover design (visit 1 to 4). The wash-out period between visits will be at least 2 weeks to a maximum of 4 weeks. Each visit will be preceded by baseline assessment measures. The safety and tolerability profiles of Namisol® will be evaluated on each intervention visit by using a standardized THC adverse effects checklist and self-reporting, vital signs, 12-lead ECG, body sway, Visual Analogue Scales (subtest feeling high), and Test for Attentional Performance (TAP, subtest alertness) and a follow up phone call the following day. Four blood samples will be collected on each visit to determine the relationship between the pharmacodynamic effects (VAS-feeling high, TAP-alertness and body sway) and the plasma concentrations of THC and its active metabolites 11‐OH‐THC and THC-COOH. In addition, a blood sample will be only collected on the first intervention day for genotyping of cytochrome P450 enzymes CYP2C9 CYP2C19 and CYP3A4.